Abstract

Concentrations of polychlorinated naphthalenes (PCNs) are reported for the first time in arctic air. The data represent combined air samples from the Barents Sea (n = 2), eastern Arctic Ocean (n = 10), Norwegian Sea (n = 2), and two land-based monitoring stations at Alert, Canada (n = 5), and Dunai Island in eastern Siberia, Russia (n = 3). Values for ∑PCN (pg m-3) were 6−49 for shipboard samples and 0.3−8 for land-based stations and were dominated by the 3-Cl and 4-Cl homologues, which accounted for 90−95% of the total mass. Average values for ∑PCB (pg m-3) for the shipboard samples were 126, 24, and 75 for the Barents Sea, eastern Arctic, and Norwegian Sea, respectively. Three-dimensional 5-day air parcel back-trajectories arriving at the ship at 850 and 925 hPa suggested that elevated PCB and PCN concentrations for shipboard samples originated in Europe. Concentrations (fg m-3) of coplanar PCBs in artic air were 3−40 (PCB 77) and 0.3−8 (PCB 126)about an order of magnitude lower than in urban air. Higher concentrations of PCB 77 and PCB 126, 347 and 5.0 (fg m-3), respectively, were found in the Barents Sea for two samples with elevated ∑PCBs. The proportion of coplanar PCBs to ∑PCBs was within the range of values reported for Aroclor and Clophen mixtures. The 2,3,7,8-TCDD toxicity of the air samples was assessed in terms of the TEQ (dioxin toxic equivalents) contribution of mono-ortho PCBs (congeners 105, 114, 118, 156), non-ortho (coplanar) PCBs (congeners 77 and 126), and dioxin-like PCNs for which toxic equivalent factors have been determined. The results show a 13−67% TEQ contribution of PCNs in arctic air, and it is concluded that further investigation of this compound class is merited.